Many people who enjoy water related activities have the problem that water entering the ear canal may not drain away for hours or even days. This can also result in a pressure differential between the inner and outer ear with resulting pain and hearing problems both during the water activity and later. The exposure of the delicate tissues of the ear to untreated water, which may contain harmful substances and infectious agents, can cause ear infections or other negative reactions.
A number of ear plugs used for a variety of different purposes are available. In Carrigan, U.S. Pat. No. 5,332,871, an earplug having a hole therethrough closed by a manually operated valve allows the user to open the valve for improved hearing without removing the plug. In Ochi et al. U.S. Pat. No. 4,540,063, an ear plug which attenuates sound waves of particular frequencies is described. Neither of these are intended to be used in the water.
A number of other available plugs are designed for protection against water entering the ear canal and to protect the ear against loud noises. In general, these use a design that simply seals off the ear canal by a variety of sealing means.
None of these ear plugs provide a watertight seal of the ear canal along with means for admitting or discharging air to minimize or prevent differential pressure across the plug, to improve hearing underwater and to allow hearing while the ear plug is sealed within the ear whether underwater or not.